Let-off mechanism for looms.



PATENTED FEB. 21, 1905.

0. H. DRAPER.

LET-OFF MECHANISM FOR LOOMS.

APPLIOATION FILED NOV. 18, 1904.

Patented February 21, 1905.

FFIQE.

PATENT CLARE H. DRAPER, OF HOPEDALE, MASSACHUSETTS, ASSlGNOR TO DRAPERCOMPANY, OF HOPEDALE, MASSACHUSETTS, A CORPO- RATION OF MAINE.

LET-OFF MECHANISM FOR LOOIVIS.

SPECIFICATION forming part of Letters Patent No. 783,183, dated February21, 1905.

Application filed November 18, 1904- Serial No. 233,260. v 7

To all? whmn it may concern Be it known that LCLARE H. DRAPER, a citizenof the United States, and a resident of Hopedale, county of Worcester,State of Massachusetts, have invented an Improvement in Let-OffMechanism for Looms, of which the following description, in connectionwith the accompanyingdrawings, is aspecification, like characters on thedrawings representing like parts.

In the well-known Bartlett let-01f motion the whip-roll or warp-guide ismoved or rocked downward at each pick by the tension of the warp, asuitable connection setting a pawl (cooperating with a ratchet throughwhich the warp-beam is rotated) in such manner that a greater or lessnumber of ratchet-teeth will be delivered when the pawl is moved forwardto a fixed point on its operating stroke. The greater the warp tensionthe larger the number of teeth which will be taken by the pawl when set,and a correspondingly greater delivery of the warp will be effected, thepawl being moved to a fixed point at each stroke by a connection betweenthe pawl-carrier and a moving part of the lay. This let-off motion isdefective because of the increased strain upon the warp due to thegreater movement of the whip-roll when the beam is nearly empty, for asthe diameter of the yarn mass on the beam decreases a greater number ofratchet-teeth must be included in the stroke of the pawl to compensatefor such decrease, and this greater movement of the whip-roll requiresgreater power to effect the same. Such increased strain or tension onthe warp results in narrower cloth, causes thin places at the time offilling-changing, and increases warp breakage. In United States Patentto Draper and Roper, No. 647,815, dated April- 17, 1900, theseobjectionable features were overcome by the employment of novel meanscontrolled by the warp tension and the diameter of the yarn mass on thebeam to determine the starting-point of each stroke of the pawl. Suchmeans includeda compound pawl-carrier with a relatively movableconnection for the members thereof, one of said members being moved insetting the pawl by means governed by the warp tension, while theposition ofthe connection between the members of the pawlcarrier wasdetermined by a controlling device dependent upon the diameter of theyarn mass on the beam. This let-ofi' mechanism has been highlysatisfactory in operation; but my present invention has for its objectthe production of a simpler form of let-off mechanism possessing thevarious advantageous features of such patented structure and free fromthe objections of the Bartlett type of let-off.

- I have in the present embodiment of my invention eliminated thecompound pawl-carrier and the follower which cooperates with theperiphery of the yarn mass on the beam, together with the connectingdevices between the follower and the compound pawl-carrier, thestarting-point of each stroke of the pawl being determined herein bymeans acting wholly through the whip-roll, so that such starting-pointis located in conformity with the combined action of the warp tensionand the diameter of the yarn mass on the beam.

Figure 1 is a right-hand side elevation of a loom with let-off mechanismembodying one form of my present invention applied thereto. Fig. 2 is adetail viewed from the opposite side of the loom of the rocking supportfor the whip-roll and some of the adjacent parts to. be described; andFig. 3 is a rear view, centrally broken out, of the whip-roll andadjacent parts.

The warp-beam B, having an attached large gear l5,the drivingshaftBcarrying-in practice a pinion (not shown) in mesh with the beam-gear Band having loosely mounted upon it the ratchet B, the friction clamp orbrake F to cooperate with the ratchet-hub, the speed-reducing gearinginclosed within the casing Gr, forming a part thereof and connected byhub g with the shaft B and the arms 5 and g, slidably connected with'afixed stud E on the loom side, may be and are all substantially as inUnited States Patent of Roper, No. 744,941, said patent being based uponthe prior patent, No. 647,815, hereinbefore referred to.

Herein the let-off pawl d", which cooper ates with and operates theratchet B is mounted on a pawl-carrier 1, loosely mounted to rock uponthe shaft B adjacent the ratchet and having a depending arm 2 pivotallycon' d on the lay-sword A substantially as in Patent No. 744,941referred to. The forward beat of the lay acts through the link to impartthe feed'or operating stroke to the pawl d and moving it to a fixedpoint on each stroke. Brackets 3 on the loom sides above the warp-beamsupport a transverse horizontal rock-shaft 4, having secured to it byset screws 5 Fig. 3, upturned arms 5, provided at or near their upperends with bearings for the journals w of the whip-roll or warp-guide W,over which the warp w passes from the beam to the lease-rods L andharnesses H, Fig. 1. On the end of the shaft adjacent the right-handside of the loom, as herein shown, an upturned arm 6 is adjustablysecured by a'set-screw 7, said arm having an elongated longitudinal slot8, in which is adjustably secured a stud 9, on which is pivoted theupper end of a link 10, its lower end being pivotally connected at 11with the pawlcarrier 1 between the pawl and the shaft 13*, on which saidpawl-carrier rocks. Adjacent the whip-roll-supporting arm 5 near theup-'turned arm 6 the hub of an arm 12 is mount spring S is secured at oneend to the loom.

side and at its other end it is attached to a downwardly and rearward] yextended arm 17, secured to the rock-shaft 4 by a set-screw 18 Fig.2.

It will be manifest from an inspection of the drawings that the warptension will rock the whip roll forward at each pick, and the greaterthe tension of the warp the greater will be the amplitude of angularmovement of the whip-roll as it rocks on the shaft 4 as a fulcrum.Consequently the arm 6 will be correspondingly rocked to a greater orless extent in conformitywith the warp tension, and the link 10 willdepress the pawl-carrier 1 more or less to determine or fix thestarting-point for each operating stroke of the let-ofl' pawl 6?. Thegreater the angle between the portions 11; of the warp leading from theyarn mass N on the beam of thewhip-roll and from the latter forward at wthe nearer will the resultant of the forces acting upon the whipthan atthe later unwinding. 'ity of. variation in the warp angle should becompensated for in order to obviate any re roll approach itsfulcrumviz., the .rockshaft 4and for a given warp tension the less willbe the amplitude of the angular movement of said whip-roll. Such anglewill be greatest when the beam is full, and,conversely, it graduallydiminishes as the diameter of such yarn mass decreases. As the upperside w of the warp angle remains substantially fixed, while the oppositeside w (formed by the warp leading from the beam to the whiproll)changes its position, it follows that the resultant of the forces actingupon the whiproll to rock it will gradually move away from the fulcrumon which the whip-roll rocks. Consequently as the diameter of the yarnmass on the beam decreases the whiproll will be rocked a greaterdistance,but without increasing the strain upon the warp at each pick,inasmuch as the increased leverage effects the desired increasedmovement without any additional warp strain, and such augmentedamplitude of movement of the whiproll will act through arm 6 and link 10to of .warp let off from the beam. As a matter of :fact, the rate ofchange in the position of the part w of the warp varies from full toempty beam for a uniform. rate of decrease in the diameter of the yarnmass that is to say, the rate of change in the angular position of thepart '90 will be very much greater per inch, say, of 'diametricaldecrease in the yarn mass when the unwinding of the beam begins than itwill i be when the beam is nearly empty, or, in -other words, the .angleinclosed by the portions' w w of the warp decreases at a faster rateduring the early unwinding of a beam This irregularquirement foradjustment of the let-off during the complete unwinding of a beam, andsuch 1 compensation 1S attained by the connectlon between the whip-rolland the pawl-carrier, such connection comprising the arm 6 and link 10.It will be manifest that the more nearly the arm6 approaches thehorizontal as itis moved downward by the forward movement of thewhip-roll the greater will be the movement of the pawl to'thestarting-point of its effective stroke, and such stroke will belonger.The setting stroke for the pawl will be less, however, for a givenangular movement of the arm 6 when the latter is at or about theposition shown in Fig. 1 than it will be for the same angular movementof the arm when nearer horizontal position. In other words, the rate ofvariation of the setting stroke does not increase until a veryconsiderable increase in the regular movement of the arm 6 1S eflected',and this increase in angular minimum.

movement of said arm is not effected until the unwinding has progressedquite far, so the increase in the rate of variation of the settingstroke of the pawl does not occur until the rate of change in theposition of the part w of the warp has reached substantially its Thusthe rapid rate of change in the one is automatically compensated for bythe slow rate of variation of the other, and vice versa, eliminating thenecessity for manual adjustment during the unwinding of the beam.

The theory of operation may be stated thus: Supposing the warp pull ortension to be uniform, the whip-roll should be swung through 4increasingly greater arcs as the yarn mass decreases, and the arm 6should correspondingly be moved through greater angles to thereby impartby degrees a lengthening stroke to the pawl (Z as the beam empties. Anincreasing angular movement of the beam should result, letting off theproper length of yarn at each pawl-stroke, increasing little by littleas the diameter of the yarn mass decreases; but if the angle between 10and w decreases at a more rapid rate at the beginning of the unwinding,as is the fact, the corresponding arcs of movement of the whip-rollwould at first appear to be so long that there would be a tendency toimpart too long a stroke to the pawl, which would result in letting offthe yarn too rapidly, presupposing the rate of increase in thepawl-strokes to be regular. Atthe beginning ofthe unwinding. however,the movements of the whip-roll are not great enough to impart sufiicientangular movement to the arm 6 to effect any practical increase of thepawl-stroke, while later as the beam empties the increasing arcs ofmovement of the whip-roll impart greater angular movements to the arm 6and the pawl-strokes are gradually lengthened therebyat a more rapidrate as the rate of decrease of the angle between w and w diminishes.The desired compensation is thus effected automatically and the yarn isneither let off too rapidly at first nor too slowly at the last. I amthus enabled to secure substantially the same warp tension during eachpick from the full to the empty beam with very simple and direct-actingmeans, the warp tension and the diameter of the yarn mass onthe beamacting conjointly and wholly through the whip-roll to determine thestarting-point of each stroke of the pawl.

The adjusting-screw 14 is provided with a head PI by which the screw canbe readily turned with the aid of a wrench or similar tool to change theangle of the arms 5 with relation to the arm 6, enlargement of the angleserving to shorten the feed-stroke of the pawl while decrease of theangle lengthens the stroke. When such adjustment is to be made, thesetscrews 5 are loosened and the whip-roll is moved with or against thepull of the warp,

according to the direction in which the screw no change in relationbetween the pawl-carrier and arm 6. If a change in the latter relationis desired, it can be effected by adjustment of the stud 9 in the slot8.

My invention is not restricted to the precise construction andarrangement herein shown and described, as the same may be modified invarious particulars by those skilled in the art without departing fromthe spirit and scope of my invention.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In let-off mechanism for looms, a warpbeam, means to rotate it,including a ratchet and pawl, an actuating device to move the pawl to afixed point at each operating stroke, a rocking whip-rollthe amplitudeof whose angular movement is controlled conjointly by the warp tensionand the diameter of the yarn mass on the beam, to maintain asubstantially uniform warp tension throughout the unwinding, and meansintermediate said whip-roll and pawl to determine the starting-point ofeach stroke of the pawl inconformity with the angular movement of thewhip-roll.

2. In let-ofi' mechanism for looms, a warpbeam, means to rotate it,including a ratchet and pawl, a pawl-carrier, an actuating devicetherefor to move the pawl to a fixed point at each operating stroke, arocking whip-roll the amplitude of whose angular movement is controlledconjointly by the warp tension and the diameter of the yarn mass on thebeam, and means intermediate the whip-roll and pawlcarrier and directlyconnected with the latter to determine the starting-point of each strokeof the pawl in conformity with the angular movement of the whip-roll.

3. In let-off mechanism for looms, a warpbeam, means to rotate it;including a ratchet and pawl, a'pawl-carrier, an actuating devicetherefor to move the pawl to a fixed point at each operating stroke, arocking whip-roll the amplitude of whose angular movement is controlledconjointly by the warp tension and the diameter of the yarn mass on thebeam, means intermediate the whip-roll and pawl-carrier and directlyconnected with the latter to determine the starting-point of each strokeof the pawl in conformity with the angular movement of the whip-roll,and an adjusting device for said means.

4. In let-off mechanism for looms, a warpbeam, means to rotate it,including a ratchet and pawl, an actuating device to move the pawl to afixed point at each operating stroke, upturned arms fulcrumed above thebeam, a whip-roll mounted on said arms and adapted to be rocked by orthrough the warp, the amp'litudeof angular movement of the whip-rollbeing controlled conjointly hy the warp tension and the diameter of theyarn mass on the 1 is turned, the adjustment so made makingbeam, tomaintain a substantially uniform warp tension throughout the unwinding,and means intermediate the whip-roll and pawl to determinethestarting-point of each stroke of the latter in conformity with theangular movement of the whip-roll.

5. In let-off mechanism for looms, a warpbeam, means to rotate it,including a ratchet and pawl, an actuatingdevice to move the pawl to afixed point at each operating stroke, a rock-shaft mounted above thewarp-beam and having rigidly attached upturned arms, a whip-roll mountedin said arms and adapted to be rocked about the shaft as a center, theangular movement of the whip-roll varying in accordance with the warptension and gradually increasing by or through the decrease of thediameter of the yarn mass on the beam, and means intermediate thewhip-roll and pawl to fix the starting-point of the pawl-strokeaccording to the amplitude of the corresponding angular movement of thewhip-roll.

6. In let-off mechanism for looms, a warpbeam, means to rotate it,including a ratchet and pawl, an actuating device to move the pawl to afixed point at each operating stroke, a rock-shaft mounted above thewarp-beam and having rigidly attached upturned arms, a whip-roll mountedin said arms and adapted to be rocked about the shaft as a center, theangular movement of the whip-roll varying in accordance with the Warptension and grad ually increasing by or through the decrease of thediameter of the yarn mass on the beam, an arm mounted on the shaft andoperatively connected with the pawl, and means to vary v the anglebetween said arm and the whip-rollsupporting arms, the connectionbetween the adjustable arm and the pawl determining the starting-pointof the pawl-stroke in conformity with the angular movement of thewhip-roll;

7.- In let-off mechanism for looms, a warpbeam, means to rotate it,including a ratchet and pawl, a pawl-carrier, an actuating devicetherefor to move the pawl to a fixed point at each operating stroke, arock-shaft mounted above the beam and having attached upturned arms, awhip-roll mounted in the latter and adapted to be rocked about the shaftas a center, the amplitude of angular movement of the whip-roll varyingwith variations in warp tension and having a gradual increase by orthrough the decrease of the diameter of the yarn mass on the beam, anarm angularlyadjustable on the rock-shaft, and a link pivotallyconnecting said arm and the pawl-carrier, to fix the starting-point ofthe latter for each operating stroke of the pawl in conformity with thecorresponding angular movement of the whip-roll. I

8. In let-off mechanism for looms. a warpbeam, means to rotate it,including a ratchet and pawl, an actuating device to move the pawl to afixed point at each pick, a rocking whiproll, and means acting whollythroughsaid whip-roll to determine the starting-point of each stroke ofthe pawl in conformity with the combined action of the warp tension andthe diameter of the yarn mass on the beam, to thereby maintain asubstantially uniform warp tension throughout the unwinding.

9'. In let-off mechanism for looms, a warpbeam, means to rotate it,including a ratchet and pawl, actuating means for the latter, includinga rocking whip-roll, and means depending on the angle of the warpbetween the beam and the whip-roll to effect increased movement of thewhip-roll while the tension of the warp remains substantially uniform.

10. In let-off mechanism for looms, a warpbeam, means to rotate it, amovable whip-roll, to govern the amplitude of angular movement of thebeam, and means to vary the movement of the whip-roll by or through achange in the position of the plane of the warp between the whip-rolland the beam while the tension of the warp remains substantiallyuniform.

11. In let-otf mechanism for looms, a warpbeam, means to rotate it,including a ratchet and a pawl, actuating means for the latter,including a rocking whip-roll, and means governed by or through themovement of the whiproll to compensate for irregular variation in theangular position of the warpbetween the full and the empty beam andthereby prevent variation in warp tension.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

CLARE H. DRAPER.

Witnesses:

GEORGE OTIS DRAPER, ERNEST W. WVooD.

